1. Field of the Invention
This invention relates to a novel polyborodiphenylsiloxane and to a novel method of its preparation.
2. Description of the Prior Art
Known conventional polyborosiloxanes are prepared mainly by the following four reactions;
Group (i) Dehydration condensation reaction of boric acid and a silanediol,
Group (ii) Dehydrochlorination condensation reaction of boric acid and a diorganodichlorosilane,
Group (iii) Dealkoxylation condensation reaction of boric acid and a diorganodialkoxysilane, and
Group (iv) Deesterification condensation reaction of an ester of boric acid and a diorganodialkoxysilane.
The reaction of Group (i) is described, for example, in U.S. Pat. No. 2,517,945, U.S.S.R. Certificate of Inventorship No. 255570, French Patent No. 1547330 and Japanese Patent Publication No. 21597/1970.